O Mouthpiece of GodEye of truthSalvation of creatures from this seething ocean of Fire!How pre-eternal your masteryHow peerless your royalty!deliverer of the soulfrom attachment's travails …

From ghazal 1310

He died in 1273, but his poetry, his depth of feeling, and his mystical insight made "Our Master" (Mowlana or Mevlana) Rumi the most celebrated mystical poet in the Islamic world, from the Balkans to Bengal and everywhere else Persian was used as a literary, historical and learned language. Artists, poets, scholars, diplomats and thinkers have recognised his superlative achievement, and in honour of the 800th anniversary of his birth, Unesco declared 2007 a commemorative year, striking a medal with the poet's imagined likeness.

Jalal ad-Din Muhammad Balkhi, known as Rumi, was born in 1207 north of the Oxus river, in Persian-speaking Central Asia. When still a boy, his family emigrated westward, settling finally in Konya, capital city of the Seljuk empire, which ruled Anatolia in the name of the Abbasid caliph at Baghdad. Rumi's father, a practicing mystic with some disciples of his own, accepted a position there, preaching in Persian. Rumi was sent to study in the reputable Arabic-speaking madrasas of Damascus and Aleppo, and returned to Konya in his 30s to assume his late father's mantle as an Islamic legal scholar and preacher.

In 1244, Shams ad-Din of Tabriz came to Konya and triggered a transformation in Rumi's mystical thinking and practice, such that he began composing poetry and practicing what Sufis called "spiritual listening" (sama), a form of meditative concentration enhanced by rhythmic movement, music and singing of mystical poetry. Rumi's later followers, the Mevlevi or "whirling dervishes" would choreograph these movements in their white skirts and cream-colored hats as the stylised "turning" of the stars and heavens. Rumi expressed the stunning mystical metamorphosis he experienced and his overpowering devotion to Shams ad-Din in lyrical verse, particularly the poetic form known as ghazal. Over the next 30 years, he composed an immense collection, or divan, of 40,000 lines of lyrical verse, much of it spoken by Rumi as if in the voice of Shams ad-Din ("The Sun of Faith"), and therefore known as The Divan of Shams of Tabriz:

Sun of Truth and Faith, pride of Tabriz! Speak!But it is your voice that mouths all my words.

From ghazal 2056

My thoughts and reflections inspired by you –As though I were your phrases and expression.

From ghazal 1683

Many of the poems in his divan express the devastating, disorienting feeling of loss that Rumi experienced when Shams left Konya, abandoning Rumi in order to wean him away from the need for a spiritual guide, and compel him to pursue his own path. Shams himself explains that he learned an immense amount from Rumi, whom he considered a great spiritual exemplar in the making. But the encounter of less than three years with Shams unleashed Rumi's muse, resulting in an ecstatic outpouring of some of the most amazing and creative imagery in all of Persian poetry – a remarkable feat, given that Rumi, like many preachers and pious scholars, was not inclined to compose poetry because of its association with the debauchery and wine-drinking of the royal courts, and the flattery of professional panegyrists.

Rumi turned to two other figures in his circle of disciples for inspiration: Salah ad-Din the Goldsmith (d. 1258) and Hosam ad-Din Chelebi, to whom Rumi intermittently dictated in the 1260s his famous Masnavi-e Ma‛navi, or "Couplets of True Meaning." The work opens with the plaintive cry of the reed flute, singing of its separation from the reed bed and the searing pain of being cut off from its source of spiritual sustenance. The 25,000 lines that follow present a loosely structured succession of tales, parables, anecdotes and vignettes in verse, narratives which Rumi uses to elaborate his mystical thought. The Masnavi (also transliterated as Mathnawi or Mesnevi) inspired innumerable commentaries in many languages, and has even been called "the Qur'an in Persian tongue," in the belief that it expresses in Persian the essence of the mystical teachings of Islamic scripture.

Rumi is thus seen, not just as an icon of Islamic civilisation (or of Afghan, Iranian, Tajik or Turkish national heritage), but of global culture. And, indeed, the popular following he enjoys in North America as a symbol of ecumenical spirituality is evident in bookstores, poetry slams, church sermons and on the internet. Some claim that Rumi is the bestselling poet in the United States, achieving great commercial success at the hands of authors who "translate" despite not speaking the original language.

Since another Persian poet, Omar Khayyam (d. 1121), once had societies dedicated to him in every corner of the Anglophone world, but is relatively little read today, we may well ask whether Rumi's recent fame in the west represents just another passing fad. But might he have something profound to say about, not only the paradigm of new age thought and spirituality, but also the mystical traditions of the other established religions?This is the first in an eight-part series which will run on Comment is free: belief on Monday mornings